Reference book for ipcc both groups for may 2013????

Hello,

Im attempting IPCC in May 2013, I need to start off my studies. So, Im planning to buy refence books... My friends suggested to get Reliance complilers as of now as i cant complete refence books of authors completely. Is it wise to get Reference books or to get Compliers.... If i had to opt Reference books, whick authors to choose... HELP!!!